In all seriousness, I would consider RData files created by R itself as it fits

• reliable (check)
• simple (call it a draw--the format is binary)
• open (check: doesn't get more open than R source code)
• interoperable (check: works everywhere R works)

Close enough for me. If by systems you mean applications rather than operating system then the last point is a fail.

Oh, and RDate is efficient as the files are now by default compressed (which used to be an option which was turned off by default).

In all seriousness, I would consider RData files created by R itself as it fits

• reliable (check)
• simple (call it a draw--the format is binary)
• open (check: doesn't get more open than R source code)
• interoperable (check: works everywhere R works)

Close enough for me. If by systems you mean applications rather than operating system then the last point is a fail.

Oh, and RData is efficient as the files are now by default compressed (which used to be an option which was turned off by default).